Highways and Urban Decentralization

This report documents a retrospective study of the relationship between highways and urban decentralization. We see decentralization as caused largely by the increased consumption of land by residents and businesses which occurs mainly because of higher incomes making land more aordable. While highways might have contributed to this eect by increasing accessibility, an empirical analysis conducted in this study did not reveal a relationship between the regionwide rate of decentralization and the time of completion of the expressways (freeways and tollways) in the Chicago area.

We also and that some of the negative consequences of decentralization might have been over-stated. For example, in the Chicago area average work-trip lengths have increased only slightly from 1970 to 1990. In addition, about three-quarters of the increases in vehicle miles traveled (VMT, a measure of congestion) is attributable to increases in the number of jobs and increases in truck travel.

We believe that attempts to reverse decentralization in order to bring about a compact growth pattern need to be considered carefully because such a reversal may come at a cost to residents and businesses in a region. Specically, average housing costs in the region may increase and its economic vitality may suer. However, we remain supportive of incentives and other similar strategies to promote more ecient use of land and, in particular, to promote productive use of
vacant land [inll] in the central city and inner suburbs. We have used a mixture of research methods to achieve these objectives. These include the development of a theoretical framework to explain the decentralization process, a review of the literature on various dimensions of the decentralization-transportation-economic development nexus and an empirical analysis of the nature and eects of the decentralization process in the Chicago area. Further, a survey of suburban businesses in the Chicago area revealed that if they needed to relocate from their current addresses, they would prefer to remain in a low-density area. The report is structured into three major parts:

1) The executive summary.

2) A summary of the entire study including our major findings.

3) A set of appendices that provide the details of each part of the study.

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